#5699. CSES2134 路径查询 II
CSES2134 路径查询 II
Path Queries II
You are given a tree consisting of n nodes. The nodes are numbered 1,2,\ldots,n. Each node has a value. Your task is to process following types of queries:
change the value of node s to x
find the maximum value on the path between nodes a and b.
Input
The first input line contains two integers n and q: the number of nodes and queries. The nodes are numbered 1,2,\ldots,n. The next line has n integers v_1,v_2,\ldots,v_n: the value of each node. Then there are n-1 lines describing the edges. Each line contains two integers a and b: there is an edge between nodes a and b. Finally, there are q lines describing the queries. Each query is either of the form "1 s x" or "2 a b".
Output
Print the answer to each query of type 2.
Constraints
Example
Input
5 3
2 4 1 3 3
1 2
1 3
2 4
2 5
2 3 5
1 2 2
2 3 5
Output
4 3